The present invention relates to a propellant filling device for use in filling a propellant into an aerosol container through a valve system of the aerosol container.
As devices for use in pressure-filling a propellant into an aerosol container, propellant filling devices such as one disclosed in Japanese Patent Application Laid-Open No. 2007-530368 (hereafter referred to as Patent Document 1) are conventionally used. It is to be noted that Patent Document 1 discloses a propellant filling device adapted to be connected to the stem side of an aerosol container to fill a propellant into a bag in the aerosol container through an ejection hole of the stem.
Among such filling devices, a filling device as shown in FIG. 8 is conventionally used as a filling device for use in through-the-valve filling, which is a general method for filling a propellant. The filling device shown in FIG. 8 is intended to be used with a general aerosol container (50) having a valve system (55) and a stem (51) whose lower end is pre-fitted to the inside of a housing of the valve system (55). As shown in FIG. 8, the filling device is connected to the stem (51)-projecting side of the aerosol container (50), which is pre-filled with aerosol content composed of a liquid concentrate and propellant, and pressurized propellant is fed into the aerosol container (50) through a supply channel (52) that communicates with a supply unit (not shown). This makes it possible to, by means of the propellant pressure, depress the stem (51) and elastically deform a stem gasket (54) inwardly to fill the propellant into the aerosol container (50) via an ejection hole (53) of the stem (51) and the stem gasket (54).
In the case of such a filling device, when the pressure on the side of the supply unit is higher than the pressure in the aerosol container (50) by a certain value or more, the stem (51) is depressed by the pressure of the propellant supplied from the supply unit, which makes it possible to open the valve system (55) of the aerosol container (50) to allow the propellant to flow from the supply unit side to the aerosol container (50) side. On the other hand, when the pressure in the aerosol container (50) becomes higher than the supply unit side pressure, it becomes difficult for the pressure of the propellant supplied from the supply unit to depress the stem (51), and therefore the valve system (55) of the aerosol container (50) closes, which makes it possible to prevent the backflow of the propellant from the aerosol container (50) side to the supply unit side. Therefore, when such a conventional filling device is used to fill propellant into the aerosol container (50) containing an aerosol content composed of the propellant and a liquid concentrate previously pressure-filled thereinto, backflow of the aerosol content contained in the aerosol container (50) previously filled thereinto can be prevented.
Further, when a water- or alcohol-based liquid concentrate having relatively low viscosity is packed in the aerosol container (50), the contact area between the propellant and the liquid concentrate can be increased by shaking the aerosol container (50) due to good flowability of the liquid concentrate. This makes it possible to easily dissolve the propellant in the liquid concentrate. Therefore, the filling device can effectively fill the propellant into the aerosol container (50).